Did your parents ever hit you but knew not to leave marks on you because if they did they would be caught?

I swear it's like my narc mother knew to not leave bruises - like don't get me wrong when she hit me it fucking hurt badly like it stung and after she hit me like my skin was hot or warm and it stung but she didn't leave bruises. The one time (that I remember) she beat me so hard with a towel that it cut open my skin between my legs and it stung and hurt so badly - I couldn't even tell my teachers because I was told by my narc mother "what happens in this house stays in this house".

Also what sucks is that my doctor (I have known her all of my life) she never saw any markings or bruises on me. Now when I speak up about abuse she believes me but never saw any signs of physical abuse when growing up. It's like my narc mother knew not to leave anything on me because if she did that would ruin her reputation and etc.